<!doctype html>
<html class="reftest-wait">
  <head>
    <title>Bug 1216842: effect-level easing function produces negative values (main-thread)</title>
  </head>
  <body>
  <div id="target"></div>
  </body>
  <script>
    var target = document.getElementById("target");
    var effect =
      new KeyframeEffectReadOnly(
        target,
        { color: ["red", "blue"] },
        {
          fill: "forwards",
          /* The function produces negative values in (0, 0.766312060) */
          easing: "cubic-bezier(0,-0.5,1,-0.5)",
          duration: 100
        }
      );
    var animation = new Animation(effect, document.timeline);
    animation.pause();
    animation.currentTime = 250;
    document.documentElement.className = "";
  </script>
</html>
